Miniature internal combustion engines of the typed used to power model airplanes, cars and boats generally use glow plugs for fuel ignition. Glow plugs are similar to spark plugs in which the gap is replaced by a filament. When a voltage is placed across the filament during engine cranking, the filament becomes sufficiently hot to ignite the primer fuel after which combustion is self-sustaining and external voltage is no longer needed.
A typical glow plug comprises a center electrode fixed within a cylindrical housing. The housing is threaded at one end for mounting into the cylinder head wall. The filament is connected between an end of the center electrode within the cylinder and the housing. The housing also has formed therein a nut for tightening and removal of the glow plug from the cylinder head wall. During ignition a power source is connected across the filament by connecting a lead to the center electrode and the housing or ground.
Heretofore, connection has been made to the glow plug by the use of alligator clips, friction and spring--clothespin type connectors. A serious disadvantage of these types of connectors is that they continually come off during engine cranking due to vibration and poor locking features. In addition such connectors pose a safety hazard due to being rotated into the propeller by engine vibration and thrown by the propeller at a high rate of speed. Further, the electrical contact provided by these connectors is unreliable and they have a poor life span.
These connectors are inconvenient to use since, as aforesaid, they continually come off, make poor electrical contact, are not easily manipulated, and often require the engine cowling to be removed during use. The connector of the present invention provides a safe, secure, reliable, and easy means for connecting a power source to a glow plug and is unaffected by engine vibration.